Pressure-actuated valve.



F. E. WILLEY,

PRESSURE ACTUATED VALVE.

APPLICATION FILED JULYZS, 1911. 1,219,410, Patented Mar. 13, 1917.

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FRANK E. WILLEY, OF

OLAREIVIONT, NEW HAMPSHIRE, A-SSIGNOE, BY MESNE ASSIGN- MENTS, TO SULLIVAN MACHINERY COMPANY, OF BOSTON, MASSACHUSETTS, A

CORPORATION OF MASSACHUSETTS.

PRESSURE-AGTUATED VALVE.

Specification of Letters Patent.

Patented Mar. 13, 1917.

Application filed July 25, 1911. Serial No. 640,492.

To all whom it may concern:

Be it known that I, FRANK E. WILLEY, a citizen of the United States, and a resident of Claremont, in the county of Sullivan and State of New Hampshire, have invented an Improvement in Pressure-Actuated Valves, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to pressure fluid engines and more particularly, though not exclusively, to pressure fluid engines of the direct-acting type such as are employed in connection with rock drills or the like.

The invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one specific embodiment.

thereof while its scope will be more particularly pointed out in the appended claims.

In the drawings:

Figure l is a sectional elevation taken through the cylinder and valve chamber of a rock-drill embodying one form of my in vention; and

Fig. 2 is a sectional elevation taken through the valve chamber, showing the valve in a diflerent position from that which it occupies in Fig. 1.

Referring to the drawings, I have there shown for the purpose of illustrating the principal features of the invention the piston 1 and cylinder 2 of a rock drill. The piston rod 3 which projects through the forward cylinder head 4 is shown broken away but these parts as well as the tool to which the forward end of the piston rod is attached and the tool holding chuck may be of any suitable and well-known construction and do not materially concern the here-' in described invention.

Referring more particularly to the controlling valve .5 the latter is of the pressureactuated piston type having a central spool or head 6 which alternately connects the supply chamber 7 with the ports 8 and 9, the former leading to the rear or head end of the cylinder just in front of the rear head or buffer 10 and the latter to the forward or tool end of the cylinder immediately behind the front cylinder head 4:. The engine may be used with steam, air, or other pressure fluid.

In the position of the valve shown in Fig. 1 pressure fluid passes from the supply chamber 7 through the port 8 to the head end of the cylinder, acting to drive the piston forward. The port 9 at that time is connected about the contracted or stem portion of the valve with one end of the exhaust space 11. lVhen the valve is reversed to the position shown in Fig. 2, the

port 9 is connected with the supply chamber 7 and the head end port 8 to the opposite end of the exhaust space 11.

To reverse the Valve, the latter is provided at opposite ends with spools 12 and 13 which work in end chambers to which pressure is alternately admitted by the movement of the piston to throw the valve. The chamber containing the head 12 is connected by a passage 1st (see dotted lines) with the groove 15 of the walls of the cylinder and the chamber containing the head 13 is connected by means of the passage 16 (see dotted lines) with the groove 17 in the cylinder walls.

These grooves are alternately uncovered bythe reciprocatory movement of the piston, the uncovering of a groove and its exposure to the pressure fluid behind the piston serving to admit pressure to that end of the valve chamber with which the said groove is connected, such admission of pressure fluid reversing the position of the valve.

The pressure fluid is exhausted from that end of the valve chamber opposite the end to which pressure is admitted by means of a circumferential groove 18 in the walls of the cylinder midway the length thereof, such groove having connection with the external atmosphere through an exhaust passage. The circumferential groove 18 communicates wlth a groove or reduced portion 19 in the walls of the piston by means of longitudinal grooves20 and 21 in the piston so that one end or the other of the valve chamber may be kept free from pressure fluid during substantially the full stroke of the piston.

The spool 6 is of greater diameter than the spools 12 and 13 so that when the valve is thrown to one position or the other, for example that shown in Fig. 1, it is there maintained by the excess pressure of the supply fluid against the central head over the pressure of the supply fluid against the smaller end head until the pressure fluid is admitted as described against the opposite end of the valve.

In a valve of this type which is reversed by pressure admitted through ports controlled by the piston, it is difficult to prevent the leakage of pressure fluid past the piston rings. Such leakage which increases with usage of the engine, is frequently sufii- .cient to reverse the valve at a time when it is not intended to be reversed. For example, in the described form of engine if there is leakage past the forward piston head, the valve may be reversed on the forward movement of the piston when the groove 17 is first covered by the rear piston head instead of later when such groove is uncovered by the rear piston head and exposed to the pressure fluid as should be the case.

In order to prevent theleakage of pressure fluid past the piston from affecting the intended action of a piston controlled valve I have provided means for venting the valve or relieving pressure which might be due to leakage from a pressure area of the valve during such lnterval as the sa d area is not intended to be exposed to pressure flu d.

For this purpose venting passages are provided'whereby pressure fluid is exhausted froni' an area of the valve during the interval when such area is intended to be in effective.

The size of such passages, however, is preferably relatively small as compared with the pistoncontrolled admission passage so that, when the latter is uncovered by the piston, the excess pressure admitted to the pressure area will reverse the valve. As soonas the valve is moved the venting passage preferably becomes ineffective.

While such passages might be otherwise located, as shown in the drawin s, they are preferably arranged in the valve itself, the valve 5 being shown as provided with two such passages one of which, 29., comprises a. longitudinal passage terminating at one end in the end of the head 13 and at the other in aradial port 23. The latter is so located that when the valve is in the position shown in Fig. 1 it communicates with the exhaust.

' On the first movement of the valve however the venting passage is closed and remains thereafter closed (see Fig. 2) until the valve is again reversed. A similar passage 24 with a port 25 is provided which, in the position of the valve shown in Fig. 2, connects the end of the head 12 with the exhaust.

Referring to Fig. 1, when the piston.

moves back it uncovers the port 15 and throws the valve to the position shown in Fig. 1. y In this position pressure 1s being exhausted through the port 16 from the end.

of the valvespool and the valve is intended to be held in that position until the piston on its forward movement has uncovered the port 16 and opened it to the live pressure fluid behind the piston, whereupon" pressure at the end of the spool 18 overcomes the pressure against the spool 6 andreverses the valve. If prior to that time any leakage of pressure fluid past the piston head and through the passage '16 reaohes'the end of the spool 13, it immediately passes off to 7 venting port 23' the latter is closed so that no further leakage of 'air can'take place.

lVhile Ihave herein shown for purposes of illustration one specific form of the invention as applied to one specific type of valve and engine, it will be understood that this is wholly for the purpose'of. illustration. and that wide deviations from the details shown may be made without departing from the spirit of the invention.

Claims: V I

1. In a pressure fluid engine, the combination with a cylinder and piston, of a pres-' sure-actuated, piston-controlled valve member controlling said piston, said valve member having provision wholly within and formed as a part of said valve member for venting the spaces at the endsgof said valve member to relieve the same from piston leakage. I

2. In a pressure fluid engine, the combination with a cylinder and piston, of a pressure-actuated, piston-controlled valve member having pressure areas alternately subjected to and freed from pressure from said cylinder, said valve member having provision wholly within and formed as a part of said valve member for venting the area which is freed from pressure. 7

3. In a pressure fluid engine, the combination with a cylinder and piston, of a pressure-actuated, piston-controlled valve member having a pressure area alternately sub jected to and freed fromipressure from said cylinder, said cylinder having a piston-controlled port for admitting thereto, and said valve member having pro vision wholly within and formed as a part of said valve me mber for rfelieving said area from the effect of piston le'akage. V; Y

4. In a pressure-fluid engine, the combination with a cylinder and piston, of a pressure-actuated, piston-controlled valve mem her having a pressure area alternately sub;

trolled port for admitting pressure fluid thereto, and said valve member having formed wholly therein a venting port for said pressure area of lesser cross-sectional area than said piston-controlled port.

5. In a pressure-fluid engine the combination with a pressure-actuated, piston-controlled valve having a pressure area alternately effective and ineiiective, a piston-controlled port for admitting pressure fluid thereto and a venting port for said pressure area of lesser cross sectional area than said piston controlled port, said venting port being rendered ineffective on the pressure actuated movement of the valve.

6. In a pressure-fluid engine the combination with a pressure-actuated, piston-controlled Valve having a pressure area alternately effective and ineffective, a piston-controlled port for admitting pressure flu id thereto and a venting port for said pressure area of lesser cross sectional area than said piston-controlled port, said venting port being rendered ineflective on the pressure actuated movement of the valve, and said venting port being formed wholly in the valve.

7. In a pressure-fluid engine the combination with a pressure-actuated valve having a pressure area, a port in said valve opening upon said area and a port in the engine for admitting pressure to said area to move the valve, said valve port being in communication with the exhaust in one position of the valve but being closed on movement of the valve to another position.

8. In a pressure-fluid engine, the combination with a unitary pressure-actuated reciprocatory valve member having a pressure area, a piston, a port controlled by the piston for alternately admitting pressure fluid to and exhausting the same from said area, said valve member being provided with a port of lesser cross sectional area for venting said pressure area.

9. In a pressure fluid engine, the combination with a piston having a centrally grooved portion, a cylinder having an exhaust port adapted to communicate with said centrally grooved portion of the piston near the mid position of the latter, a valve provided with opposed pressure areas for alternately moving the same in opposite directions, a port for each pressure area adapted to admit pressure thereto, such port being alternately closed to live pressure fluid and to the centrally grooved portion of the piston and venting passages arranged in said valve communicating each with one of said pressure areas and being adapted in one position of the valve to open the same to the exhaust and in another position thereof to close the same to the exhaust.

10. In a pressure fluid engine, the combination with a piston and cylinder having an admission port and two exhaust ports on opposite sides, respectively, of said admission port, of a pressure-actuated piston-controlled valve provided with venting ports for alternately placing opposite end areas of said valve in connection with said exhaust ports.

11. In a pressure fluid engine, the combination with a piston and a cylinder having an admission port and two exhaust ports on opposite sides, respectively, of said admission port, of a pressure-actuated, piston-controlled valve having a central spool controlling said admission port, and end spools to alternately open and close said exhaust ports, said valve being provided with venting ports adapted to vent the end areas of said valve to said exhaust ports.

12. In a pressure fluid engine, the combination with a piston and cylinder having an admission port and two exhaust ports on opposite sides, respectively, of said admission port, of a pressure-actuated piston-controlled differential valve having a central spool of relatively large area, controlling said admission port, and end spools of relatively smaller area, to alternately open and close said exhaust ports, said valve being provided with venting ports adapted to vent the end areas of said valve to said exhaust ports.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses. 1

FRANK E. WILLEY.

Witnesses:

C. J. JoNEs, E. A. TRACY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

